where "../inc/hotlingo_client.js" is the actual directory where you have located
the Hot Lingo support scripts (available for download here).

SpellCheckFrame()

Invoking
Hot Lingo

To invoke Hot
Lingo, call the function SpellCheckFrame()
that is found in the hotlingo_client.js include. This function returns false
if the spell check could be done - most likely due to not having Hot Lingo
installed.
The Spell Check button code follows: